Conventionally, a game-machine operation-member rotation structure has been known in which an operation member is turned right and left that is attached to a rotation shaft which is supported so as to rotate. FIG. 9 is a side view of a conventional game-machine operation-member rotation structure. A conventional video game apparatus is provided with a dummy steering wheel 100 as the operation member. To this dummy steering wheel 100, the game-machine operation-member rotation structure is attached which includes: a main shaft 102 which has a rotation shaft 102a that is supported on a pair of bearings 101 so as to rotate, and a screw shaft 102b that is connected to this rotation shaft; a moving plate 103 which is screwed on the screw shaft 102b; a pair of columnar support shafts 104 which each penetrate a hole that is formed in each predetermined position above and below this moving plate 103, and extend in the directions parallel to the main shaft 102; and a stopper 105 which is disposed at each end of this support shaft 104.
If an operator turns the above described dummy steering wheel 100 to the right from its middle position (i.e., the position in which the moving plate 103 is in the position shown in FIG. 9), the main shaft 102 also rotates clockwise. This rotation of the main shaft 102 causes the moving plate 103 to move, along the support shafts 104, in the directions apart from the dummy steering wheel 100. Then, if the dummy steering wheel 100 is turned to the right by one or more rotations to reach a predetermined position, then the moving plate 103 comes into contact with the stopper 105, so that its further movement is restricted. On the other hand, if the dummy steering wheel 100 is turned to the left, the main shaft 102 also rotates counterclockwise. This causes the moving plate 103 to move, along the support shafts 104, in the directions close to the dummy steering wheel 100. Then, if the dummy steering wheel 100 is turned to the left up to a predetermined position beyond one rotation, then the moving plate 103 comes into contact with the stopper 105. Thereby, the dummy steering wheel 100 is restrained from being further turned.
In such a conventional game-machine operation-member rotation structure, a screw shaft and a moving plate screwed on this will change a rotational force which is given to an operation member into a movement force in the thrust directions. Then, the moving plate moves on to a predetermined position and comes into contact with a stopper, so that its movement is stopped. Therefore, when the moving plate is kept in contact with the stopper, or immediately before it comes into contact, if the rotational force which is applied on the operation member continues or remains, then after the moving plate has come into contact with the stopper, an excessive rotational force works on the screw-structure part between the screw shaft and the moving plate. Then, this screw-structure part (e.g., a thread) can be worn out, deformed and then broken, thus producing so-called shakiness. Besides, the stopper can be destroyed, and in an aspect which has the function of automatically restoring the operation member to a reference position, the above described shakiness may affect a control system for the restoration.
In order to resolve the above described disadvantages, it is an object of the present invention to provide a game-machine operation-member rotation structure and a video game apparatus which are capable of stably holding a position in which a moving body comes into contact with a stopper, even if an excessive rotational force is applied on an operation member.